Vaccine safety The majority of Australians are happy to share medical records freely with researchers to help quickly pick up any unforeseen side-effects of childhood vaccines, a new study suggests.

The authors, reporting online in the journal Vaccine, say the findings support the linking of hospital and immunisation register records to overcome the limitations of Australia's current "passive" surveillance of vaccines.

"Australia's passive reporting system has been compromised," writes Jesia Berry, of the University of Adelaide, and colleagues, citing the case the 2010 flu vaccine.

"[T]he system failed to readily detect an increased incidence of febrile convulsions within 24 hours of receiving the [vaccine] among children aged five years and under."

While most vaccine side-effects should be picked up before they are widely used, some only become evident later, says Berry.

She says in Australia post-market surveillance of vaccine safety relies on parents and doctors picking up problems and then alerting federal or state authorities.

But, says Berry, this system can be unreliable and slow.

Sometimes an adverse reaction is delayed and not recognised as being related to a vaccine, she says.

And once reports are received by authorities they must be collated and committees convened to investigate - a process that can take months.

"Some of the reports [on the flu vaccine] didn't come out until four or five months after they started to suspect there was a problem," says Berry.

Data linkage

Berry says a more reliable and effective surveillance system would be to validate passive reporting with a method called data linkage.

This would involve linking hospital records with data from the national immunisation register to see if there is any correlation between vaccines and adverse effects at a population level.

Once a threshold of an acceptable adverse reaction rate is breached this would give authorities an immediate alert, says Berry.

Berry says this "data linkage" system is used in the US, allowing a weekly report on vaccine adverse reactions.

But, she says, before such a system can be introduced in Australia, one of the issues that need to be considered is patient consent to sharing their medical records for the purposes of research.

Privacy

Berry says Australians are very privacy-conscious and usually require their consent to be given every time before their data is used, regardless of whether it's identified as being theirs or not.

As part of her PhD, supervised by statistician Professor Philip Ryan and paediatrician Professor Michael Gold, Berry carried out a survey of randomly-selected 2002 households in South Australia to investigate people's perspectives on consent for data linkage.

She found that 96.4 per cent of those surveyed supported data linkage for surveillance of vaccines, and most were happy for records to be shared without specific consent being sought beforehand.

She says under the current data linkage proposal, clinical data researchers would never be able to identify whose clinical data they were working with.

Answering questions

Berry says linking data like this can quickly pick up genuine problems with vaccines, or alternatively help reassure parents.

"You need an active surveillance system to test any hypotheses you might have about what vaccines might cause or might not cause," she says.

Berry says data linkage is quite advanced in Scandinavian countries and made it possible for Danish researchers to dismiss the link between vaccination and autism.

High vaccination rates

Berry's new survey found 53.1 per cent of respondents were very or somewhat concerned that a vaccine could cause a serious reaction.

Despite this 92.4 per cent of the parents surveyed reported every child in their care as being fully immunised.

Berry's research was carried out as part of the ARC-funded Vaccine Assessment Using Linked Data (VALiD) project, which aims to investigate vaccine safety by linking Australian Childhood Immunisation Register (ACIR) and National Death Index and emergency department attendance data.

The Department of Health and Ageing has approved use of ACIR data for the study, but says it is too soon to tell if data linkage is the way forward for vaccine surveillance.

"This study is ongoing and it is not yet possible to determine the effectiveness or feasibility of this methodology," a spokesperson for the department told ABC Science Online.